Finnish Wikipedia was created in 2002, so it will celebrate its 15th birthday next year, at the same year when Finland celebrates the 100th anniversary of its independence!
You can read the press release in Finnish about the milestone here: https://fi.wikipedia.org/wiki/Wikipedia:Lehdistötiedote_400_000_artikkelia
Finnish Wikipedia milestones:
100 000 articles: 11 February 2007
200 000 articles: 12 April 2009 (+2,2 years)
300 000 articles: 26 June 2012 (+3,2 years)
400 000 articles: 29 August 2016 (+4,2 years)
And if we are continuing with this tempo, Finnish Wikipedia will have half a million articles in October 2021.
Did you know we even have a page where you can guess the date when the 500 000th article will be created? See https://fi.wikipedia.org/wiki/Wikipedia:500_000._artikkelin_veikkaus
tip: there’s no 2021 added yet, be the first one? 😉